Isoenzymes and activity of laccases produced by Pleurotus ostreatus grown at different temperatures

Pleurotus ostreatus produces laccase isoforms depending on the conditions in which it grows, it has been suggested that the presence of inducers, the pH of the culture medium as well as the type and concentration of carbon and nitrogen sources promote the production of these isoforms, however, the effect of temperature of Pleurotus ostreatus growth on its production of laccase isoforms has not been evaluated. In this study, Pleurotus ostreatus was grown in solid-state fermentation at different temperatures (10, 15, 20, 25, 30 and 35 °C) and the activity and isoforms number of laccases produced in each bioprocess was determined. At 10 and 35 °C there was no growth of the fungus. The activity of laccases was different in each fermentation, being at 25 ºC where the highest value was observed (20000 U L-1). The laccase isoenzymes pattern was also different depending on the incubation temperature of the fungus, it was observed in some times of the culture, 4 isoforms in the fermentations incubated at 15 and 20 ºC, 3 isoforms at 25 ºC and 2 isoforms at 30 ºC. These results show that the growth temperature of Pleurotus ostreatus modifies its patterns of activity and of isoforms of laccases.

Keywords: laccases; Pleurotus; solid-state fermentation; temperature; zymograms.